But wages are as low as $37 a month, with some employees working 10-15 hours per day

Some retailers are getting worried about their reputation

"There is no fire station within a 30 kilometre radius of the factory," he said.

The blaze appeared to have been started by a malfunctioning knitting machine which had caught fire on a number of previous occasions.

A reporter at the scene found work order books containing names of the factory's clients in September which included US brand Gap, British retailer Next, Swedish fashion label H&M, Australia's Target, French supermarket Carrefour and Walmart brand George.

The collapse of the Rana Plaza factory bloc in April killed 1,129 people in the nation's worst industrial disaster.